Which of the following functions is not odd? 1) f(x) = sinx 2) f(x) = sin2x 3) f(x) = x³+1 4) f(x) = 5) f(x) = ∛(2x) explain why 4 and 5 isn't the answer

f(x) =x³ + 1 is not an odd function

Step-by-step explanation:

We are asked about odd functions

If f(x) be a function and f(-x) =-f(x)

then f(x) is an odd function

1) f(x) = sinx

Here f(-x) = sin(-x)

=-sinx                                          sin(-x) = -sinx

Therefore it is an odd function

2) f(x) = sin2x

f(-x) = sin 2(-x)

= sin (-2x)

=-sin2x = -f(x)

Therefore it is an odd function

3) f(x) = x³ +1

f(-x) = (-x)³ + 1

= -x³+1

For odd function it should be -(x³+1)

Hence it is not an odd function

4) f(x) =

f(-x) =

=

= -f(x)

Therefore it is an odd function

5) f(x) = ∛(2x)

f(-x) =∛(-2x)

= - ∛(2x)

=- f(x)

Hence it is an odd function

∴ 3) f(x) = x³+1 is not an odd function